Electrochemical cells are known which allow production of electricity by an oxidation-reduction reaction between an oxidizing fluid and a reducing fluid. Notably, cells of a fuel cell are known allowing production of electricity by an oxidation-reduction reaction between a fuel, comprising hydrogen, and an oxidizer, comprising oxygen. The fuel is injected into an anode conduit and the oxidizer is injected into a cathode conduit of the cell, an electrolyte layer ensuring the seal between both of these conduits, allowing ion exchanges. Because of these ion exchanges, the hydrogen contained in the fuel may react with the oxygen contained in the fuel in order to produce water, by generating electrons at the anode. This ensues, during operation of the cell, the establishment of a potential difference between both sides of the electrolyte, this potential difference may be utilized for generating an electric current.
However, the potential differences established within a cell of a fuel cell remain low, of the order of 0.6 to 1.0V. Also, in order to obtain an utilizable output voltage, the cells are most often stacked and electrically connected in series with each other, within what is commonly called a fuel cell.
The fuel cell is generally electrically connected to an electric converter giving the possibility of shaping the current leaving the fuel cell for its consumption by a load. The electric converter is controlled by a control module which acts on the converter so that the current leaving the converter is adapted to the load. The control module typically adjusts the voltage of the output current and when the output current is an alternating current, the frequency of the output current.
The most often, the fuel cell is equipped with an emergency stopping module for stopping the fuel cell in the case of malfunction, for example in the case of a loss of seal of the electrolyte layer of one of the cells. The emergency stopping module is generally associated with a unit measuring the voltage on the terminals of the cells of the fuel cell in order to detect said malfunction.
A problem currently encountered on known fuel cells is that the emergency stopping untimely triggers because of a too large electric power being taken on the fuel cell. This occurs in particular when the fuel cell is cold and that the requested power increases suddenly, or when the fuel cell is old and has limited performances.
U.S. Pat. No. 6,428,917 proposes regulation of the maximum output current leaving the fuel cell. For this purpose, U.S. Pat. No. 6,428,917 proposes an electric energy production system with a fuel cell comprising a control module programmed for inferring a maximum output current at the outlet of the fuel cell from the comparison between the lowest cell voltage and a threshold voltage, and for transmitting to the electric converter a set value representative of said maximum current.
However, this production system requires computers carrying out complex operations. Accordingly, the production system is difficult to produce and is costly. Further, the control module is not very adaptive for fuel cells having a large number of electrochemical cells, for example greater than a hundred.
Electrochemical cells are also known giving the possibility of producing an oxidizing fluid and a reducing fluid by electrolysis of a third-party fluid. Notably, water electrolysis cells are known giving the possibility of producing hydrogen and oxygen. The water is injected into an anode or cathode conduit of the cell, an electrolyte layer ensuring the seal between both of these conduits, by allowing ion exchanges. Under the influence of an electric potential difference applied between both conduits, the water decomposes into positive hydrogen ions and into negative oxygen ions, the ions of a same sign migrating through the electrolyte layer to the other conduit of the cell. The oxygen ions are thus separated from the hydrogen ions. The oxygen ions then yield their electrons and are thus converted into dioxygen, while the hydrogen ions receive electrons and are thus converted into dihydrogen.
The electrolysis cells are most often stacked and electrically connected in series with each other, within what is currently called an electrolyzer.
The electrolyzer is generally electrically connected to an electric converter giving the possibility of shaping a supply current of the electrolyzer provided by an electric source. The electric converter is controlled by a control module which acts on the converter so that the current leaving the converter is adapted to the electrolyzer. The control module typically adjusts the voltage of the supply current.
Most often, the electrolyzer is equipped with an emergency stopping module for stopping the electrolyzer in the case of a malfunction, for example in the case of over voltage on the terminals of one of the cells. The emergency stopping module is generally associated with a unit measuring the voltage on the terminals of the cells of the electrolyzer in order to detect said malfunction.
The known measurement units are however not very suitable for measuring the voltages on the terminals of the cells of large electrolyzers comprising typically more than a hundred electrochemical cells.